1. Field of the Invention
This invention relates to a substrate processing method and a substrate processing apparatus for performing, for example, a coating processing of a resist solution, a developing processing and the like on a substrate such as a semiconductor wafer, a glass substrate for a liquid crystal display and the like.
2. Description of the Related Art
In a lithography of a fabricating process of a semiconductor device, a resist is coated onto the surface of a semiconductor wafer (hereinafter referred to as a xe2x80x9cwaferxe2x80x9d), and thus coated resist is subjected to an exposure processing in accordance with a predetermined pattern and further to a developing processing to form a resist film of the predetermined pattern. A series of processings like this is performed by a system in which an exposure unit is connected to a coating/developing unit.
FIG. 10 is a plane view showing a conventional example of these units, in which a cassette C housing 25 substrates, for example, semiconductor wafers W is carried into a cassette stage 1 of a cassette station A1. A process station A2 is connected to the cassette station A1, and further, a not-shown exposure unit is connected to the process station A2 through an interface station A3.
The wafer W inside the cassette C on the cassette stage 1 is removed by a delivery arm 11 and sent to a coating unit 13 through a delivery section in a shelf unit 12 to be coated with the resist. Subsequently, the wafer W is transferred by the route of a wafer transfer means 14xe2x86x92a delivery section in a shelf unit 15xe2x86x92the interface station A3xe2x86x92the exposure unit to be exposed. The exposed wafer W is transferred to the process station A2 by the reverse route, developed in a not-shown developing unit provided in the lower tier of the coating unit 13, and then transferred by the route of the wafer transfer means 14xe2x86x92the delivery section in the shelf unit 12xe2x86x92the cassette C.
It should be noted that each shelf of the shelf unit 12, 15 is structured as a heating section, a cooling section, the delivery section of the wafer W, a hydrophobic section and so on, and before a resist coating and the developing processing, a heating processing and a cooling processing are performed in this order in the shelf unit 12, 15 in order to perform the resist coating or the like at a predetermined temperature. Incidentally, the delivery arm for delivering the wafer W between the process station A2 and the exposure unit is shown as number 16.
Further, a process area which comprises the coating unit 13 and the developing unit and a transfer area in which the wafer transfer means 14 is arranged are partitioned off in the process station A2, and an atmosphere of a clean room is taken in as well as the air the temperature and the humidity of which are adjusted in a predetermined manner is flowed in the process area, whereby the area have, so to speak, the atmosphere which is adjusted with high accuracy.
Note that the present inventors find out that a film thickness of a resist and a developing line width are highly dependent on a processing temperature, as shown with a temperature dependency of the film thickness of the resist in FIG. 11 and with a temperature dependency of the developing line width in FIG. 12, and if the processing temperature changes 2xc2x0 C., the film thickness of the resist and the developing line width change significantly.
In a coating/developing unit, a wafer W undergoes a predetermined processing in, for example, hydrophobic sections in shelf units 12, 15, then cooled to a predetermined temperature in a cooling section, and coated with a resist in a coating unit 13, in which the wafer W is transferred from the cooling section to the coating unit 13 via a transfer area the temperature and the humidity of which are not adjusted. Therefore, even if the temperature of the wafer W is adjusted in the cooling section, it is influenced by the temperature of the transfer area during the subsequent transfer, and the temperature of the wafer W in coating the resist differs from that of the scheduled in the end, which may results in a change in the film thickness of the resist and a worse uniformity of the film thickness.
In order to prevent this, it may be possible to think of making an entire process station A2 to be an atmosphere adjusted with high accuracy in which the temperature and the humidity are adjusted, which causes a disadvantage that an increasing area for adjusting its atmosphere costs more.
An object of the present invention is to provide a substrate processing method and a substrate processing apparatus which can improve the uniformity of the processing by performing a coating processing of a coating solution in a state with the temperature and the humidity of a substrate adjusted with high accuracy.
To attain this object, the substrate processing method of the present invention for transferring the substrate cooled by the cooling plate to a coating processing section and for coating the processing solution onto the substrate in the coating processing section, comprising the steps of: detecting the temperature of an area to where the substrate is transferred, and adjusting the temperature of the substrate cooled by the cooling plate based on the detected temperature so that the temperature of the substrate transferred to the coating processing section is made to be the same with a supplying temperature of the processing solution.
The substrate processing method like this is, in concrete, performed by the substrate processing apparatus having a cassette station which includes a mounting portion for mounting a substrate cassette housing a plurality of substrates and a delivery device for delivering the substrate to the substrate cassette mounted on the mounting portion, and the process station connected to the cassette station for processing the substrate transferred by the delivery device, and the process station comprises: the cooling plate for cooling the substrate, the coating processing section for coating a processing solution onto the substrate, a substrate transfer device for transferring the substrate cooled by the cooling plate to the coating processing section, a temperature/humidity detector for detecting the temperature of the area to where the substrate is transferred by the substrate transfer device, and a control section for adjusting the temperature of the cooling plate so that the temperature of the substrate when transferred to the coating processing section becomes the same with the coating temperature of the processing solution based on a detected value by the temperature/humidity detector.
In the structure like this, the temperature of the area to where the wafer is transferred is detected and the temperature of the substrate which is cooled by the cooling plate is adjusted accordingly based on a detected value so that the temperature of the substrate when transferred to the coating processing section becomes the coating temperature of the processing solution, whereby, the coating processing can be performed while maintaining the temperature of the substrate with high accuracy, which makes it possible that a formation of an uneven processing due to the temperature change can be prevented and a uniformity of the coating processing can be improved.
Further, the substrate processing method of the present invention for transferring the substrate cooled by the cooling plate to a coating processing section and for coating the processing solution onto the substrate in the coating processing section, further comprising the step of: transferring the substrate from the cooling plate to the coating processing section while supplying the gas with its temperature adjusted onto the surface to be processed of the substrate.
The substrate processing method like this is performed by the substrate processing apparatus having the cassette station which includes the mounting portion for mounting the substrate cassette housing a plurality of substrates and the delivery device for delivering the substrate to the substrate cassette mounted on the mounting portion, and the process station connected to the cassette station for processing the substrate transferred by the delivery device, and the process station comprises: the cooling plate for cooling the substrate, the coating processing section for coating the processing solution onto the substrate, the substrate transfer device for transferring the substrate between the cooling plate and the coating processing section, and a gas supply part for supplying the gas to the surface to be processed of the substrate with its temperature adjusted, while the substrate is transferred from the cooling plate to the coating processing section by the substrate transfer device.
In the structure like this, the substrate is transferred from the cooling plate to the coating processing section while supplying the gas with its temperature adjusted onto the surface to be processed of the substrate so that the temperature change can be prevented during the transfer, the coating processing can be performed in a state with the temperature of the substrate adjusted with high accuracy, and the uniformity of the processing can be improved. Here, it is preferable that the temperature of the gas which is supplied from the gas supply part to the surface to be processed of the substrate is adjusted to a processing temperature in the coating processing section, in which case the temperature change of the substrate during the transfer can be further prevented and the uniformity of the processing can be further improved.
In concrete, the present invention is structured to include an exposure unit which is provided to the opposite side of the cassette station of the process station and an interface station connected to the opposite side of the cassette station of the process station for delivering the substrate between the process station and the exposure unit, in which the coating processing section is for performing the coating processing onto the substrate, and further structured to include the exposure unit which is provided to the opposite side of the cassette station of the process station and the interface station connected to the opposite side of the cassette station of the process station for delivering the substrate between the process station and the exposure unit, in which the coating processing section is for performing the developing processing onto the substrate which is exposed in the exposure unit.
According to another aspect, the substrate processing apparatus of the present invention includes the cassette station which includes the mounting portion for mounting the substrate cassette housing a plurality of substrates and a delivery means for delivering the substrate to the substrate cassette mounted on the mounting portion, and the process station connected to the cassette station for processing the substrate transferred by the delivery means, and the process station comprises: the coating processing section for coating the processing solution onto the substrate, a substrate transfer means for delivering the substrate to the coating processing section, the cooling section for cooling the substrate, and a transfer means for transferring the substrate between the coating processing section and the cooling section, which is characterized in that the coating processing section and the cooling section are provided adjacently to each other and that a transfer area which is exclusive to the transfer means is formed adjacently to the coating processing section and the cooling section.
In the structure like this, the transfer of the substrate between the coating processing section of the process section and the cooling section for cooling the substrate is performed by the exclusive transfer means via the exclusive transfer area, and hence a burden imposed on the substrate transfer means can be lightened.
On this occasion, the transfer area which is exclusive to the transfer means may be a spatially closed area partitioned off from other areas, in which case the influence of heat by a heating section becomes less because the area is separated from the heating section for heating the substrate. Therefore, the temperature change of the substrate can be retarded during the transfer of the substrate in the area, a formation of the uneven processing due to the temperature change can be prevented, and a uniformity of the coating processing can be improved. Here, when the temperature of the transfer area which is exclusive to the transfer means is adjusted, the temperature change of the substrate can be further prevented during the transfer of the substrate in the area and the uniformity of the coating processing can be further improved.
Further, the cooling section may be a spatially closed area partitioned off from other areas, in which case the influence of heat from other areas becomes less and hence a temperature adjustment becomes easier. Furthermore, the coating processing section may be a spatially closed area partitioned off from other areas, in which case each of the coating processing section, the cooling section and the transfer area is spatially closed and hence it is possible to adjust the atmosphere in each area separately and it can be applied to the processing in which the atmosphere in each section is different.
These objects and still other objects and advantages of the present invention will become apparent upon reading the following specification when taken in conjunction with the accompanying drawings.